Flotation material



Patented Aug. 30, 1938 UNITED STATES FLOTATION MATERIAL Merrill W. MacAfee, Berkeley, Calif., assignor to Great Western Electro-Chemical Company, a corporation of California No Drawing. Application September 17, 1935, Serial No. 40,929

7 Claims.

This invention relates to a composition of matter useful in flotation. More particularly this invention is concerned with provision of a composition of matter enabling. dixanthogens t be employed in flotation.

As is well known, dixanthogens are obtained from the oxidation of xanthates by oxidizing agents. 'Their use in flotation has heretofore been suggested and investigated. However, they have not gone into wide application. Gaudin in Flotation, McGraw-Hill Book Company, 1932, at page 72, states that unlike the alkali xanthates, dixanthogens are very little soluble in water. Their insolubility is one of the factors that has mitigated against their general use in sulphide flotation. This statement is quite true and very few mills in this country utilized dixanthogens on a commercial scale, prior to the present invention. The water insolubility of the dixanthogens has made it difficult to feed them properly as well as preventing their adequate incorporation in the pulp undergoing flotation. Dixanthogens have been added in ball 1111115 to the ore being ground but this is only partly successful.

In accordance with this invention, I have been ableto feed dixanthogens with accuracy and incorporate them directly in the pulp undergoing flotation. The result is that mills are accepting dixanthogens for commercial operation because they .are able to achieve results not possible with the best flotation agents known heretofore, such as potassium ethyl xanthate, potassium secondary butyl xanthate and potassium amylxanthate as well as the dithiophosphate compounds.

I have observed that flotation reagents such as dixanthogens tend to depress the froth during the flotation operation. This further complicates the operation and mitigates against the employment of the dixanthogens.

both these undesirable effects of dixanthogen can be overcome by incorporating the dixanthogen in a suitable solvent therefor, preferably one which is not a frothing agent per se but which 4.5 nevertheless neutralizes and offsets the depressing efiect on the froth of the reagent. Such a solvent I have found in the alcohols such as methanol, isopropyl alcohol, secondary butyl alcohol, primary butyl alcohol, amyl alcohol,

50 Pentasol (a mixture of amyl alcohols), and the various primary, secondary and tertiary amyl alcohols, and other organic solvents such as acetone. Any solvent can be used which is water miscible, of low vapor pressure and miscible with 56 the dixanthogen.

I have found that The solvent employed is preferably anhydrous and anhydrous ethyl alcohol can be used although the ordinary commercial form includes such a percentage of water that only about a 5% concentration of the reagent can be secured. An 5 anhydrous solvent is desirable for water limits the quantity of dixanthogen which the solvent will carry. When the solvent carrying the dixanthogen is added to the water in the flotation circuit, the solvent, being water soluble, leaves 10 the "dixanthogen behind but in a very well dispersed condition. In practice I usually make up a. 50-50 mix by weight of the reagent and alcohol. This mixture is characterized by its stability under ordinary conditions, a factor of 15 importance and one which usual solvents do not possess. The solvent also preferably has a low vapor pressure at ordinary temperatures for otherwiseit will evaporate in the feeder to leave the dixanthogen remaining. It is also prefer- 20 ably non-hygroscopic because if it is otherwise it will precipitate dixanthogen'upon exposure to the atmosphere.

It is to be noted that the solvents employed are not frothing agents. I prefer not to incor- 25 porate the flotation reagents in frothing agents such as pine oil and the like because of the great power of the dixanthogens in flotation. Thus I have successfully floated minerals with the composition of the present invention using very 30 minute quantities while larger quantities of a frothing agent were necessary. By utilizing a solvent which is not a frother, the froth control and the flotation reagent control are simplified. The reagent of this invention can be readily 35 used in flotation after the manner of the Douglass Patent No. 1,943,758 and my prior Patent No. 2,061,201.

The use of the solvents of the present invention is to be further distinguished from this 40 prior art practice where in one flotation reagent would be incorporated a second agent, the second agent acting as a solvent for the first and having the additional capacity of also acting as a mineral collector. In this instance, the second agent is used to neutralize the froth depressing efl'ect of the first reagent and is in itself incapable of effecting an appreciable mineral recovery.

The invention is applicable to any dixanthogen whether aryl or alkyl and whether it is derived from a primary, a secondary or a tertiary alcohol. It includes particularly the dixanthogens of such alcohols as ethyl, propyl', butyl and amyl alcohol, and their isomers as well as the secondary alcohols, iso-propyl, secondary butyl,

v same dixanthogens in their concentrated state.

This I attribute to activation of the dixanthogen, for, so far as the ore is concerned, the use of diluted dixanthogen gives recoveries not secured with a concentrated material. These results have been particularly evident on gold and silver ores, particularly in the lead separation from the gold and silver ore at El Potosi mine in Mexico.

I claim:

1. As a composition of matter, a dixanthogen dissolved in a substantially anhydrous water soluble aliphatic monohydric alcohol, said alcohol being water miscible and having a frothing power only suflicient substantially to offset any froth depressant power of said dlxanthogen.

2. As a composition of matter, a dlxanthogen dissolved in secondary butyl alcohol.

3. As a composition of matter, a dixanthogen dissolved in secondary amyl alcohol.

4. As a composition of matter, a secondary butyl dixanthogen dissolved in secondary butyl alcohol.

5. As a composition of matter, a dixanthogen dissolved in a substantially anhydrous water soluble aliphatic monohydric alcohol, said alcohol being water miscible and having a frothing power only sufi'icient substantially to offset any froth depressant power of said dixanthogen, and being present in the mixture with said dixanthogen in about an equal weight.

6. In the process of concentrating ores and minerals by flotation, the step which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of a dixanthogen diluted with a substantially anhydrous water miscible aliphatic monohydric alcohol as a solvent for the dixanthogen prior to incorporation of the dixanthogen in the pulp.

7. As a composition of matter, a dixanthogen dissolved in a substantially anhydrous secondary aliphatic monohydric saturated unsubstituted alcohol.

MERRILL W. MACAFEE. 

